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What are the built in protections provided in 415 V breaker?
a. DINF (making current magnetic release) This consists of a laminated magnetic circuit. This is placed under the lower current terminal pole. This is provided for all the three poles. It has a core that rotates in the air gap. It is held by spring. During protection the magnetic forces developed ovRead more
a. DINF (making current magnetic release)
This consists of a laminated magnetic circuit. This is placed under the lower current terminal pole. This is provided for all the three poles. It has a core that rotates in the air gap. It is held by spring. During protection the magnetic forces developed overcome the spring tension and the core is attracted. The mechanical force developed is used to trip the breaker. This protection acts during the closing of breaker if any fault exists. The current is set to 5 times the rated current.
b. DIRS (short time magnetic release)
The construction is same as DINF, but it has a mechanical timer, which can be set accordingly. This protection acts when any fault comes during breaker in service. The current rating is set to 3 to 8 times the rated current.
c. DIT – S (thermal over load protection)
This consists of a three bimetallic strip, which gets heated up when over loaded and trips the breaker by a lever. It is placed in front of the breaker. Setting range is 60% to 100%.
See lessMention the commissioning tests on breaker and bus bars.
Breaker a. Milli volt drops test between the interrupting contacts and between the isolator contacts. b. Closing and opening timing of the breaker for 5 times. c. Checking whether the breaker trips or closes when the logics are fulfilled. Bus bars a. Milli volts drop test for the contact resistanceRead more
Breaker
a. Milli volt drops test between the interrupting contacts and between the isolator contacts.
b. Closing and opening timing of the breaker for 5 times.
c. Checking whether the breaker trips or closes when the logics are fulfilled.
Bus bars
a. Milli volts drop test for the contact resistance value.
b. Tightness of the joints.
c. IR values between phase to phase and phase to ground.
See lessExplain clearly the three positions in 415 V breaker.
The three positions in 415 V breaker are.a. Service position: Power connections and control connections are available to the breaker. b. Test position: Power connections are cut off but control connections are available to the breaker and it can be tested. c. Disconnect position or rack out positionRead more
The three positions in 415 V breaker are.
a. Service position: Power connections and control connections are available to the breaker.
b. Test position: Power connections are cut off but control connections are available to the breaker and it can be tested.
c. Disconnect position or rack out position: This is for maintenance of the breaker and in this positions both the control and power connections are not available.
See lessWhat is the purpose of spring charging in 415 V breaker?
If the breaker is to be closed and tripped manually the closing time and tripping time would vary from person to person. Also it would not be very fast. So spring charging is provided. It gives uniform timings irrespective of the operator and its action is fast and closing and tripping time is veryRead more
If the breaker is to be closed and tripped manually the closing time and tripping time would vary from person to person. Also it would not be very fast. So spring charging is provided. It gives uniform timings irrespective of the operator and its action is fast and closing and tripping time is very less.
See lessWhat do mean by trip free system in breaker?
In trip free the breaker is free to trip at any time. If both close and trip signal is present at same time (instant) the breaker will attempt to close and positively trip. When the breaker trips it will not close again even if closing signal exists because of anti pumping feature.
In trip free the breaker is free to trip at any time. If both close and trip signal is present at same time (instant) the breaker will attempt to close and positively trip. When the breaker trips it will not close again even if closing signal exists because of anti pumping feature.
See less